NATURE 


THURSDAY, MAY 13, 1915. 

PHYSICAL CONSTANTS. 
Société Francaise de Physique, Recueil de Con- 
stantes Physiques. By Prof. H. Abraham and 
Prof. P. Sacerdote. Pp. xvi+753. (Paris: 
Gauthier-Villars, 1913.) Price 50 francs. 
HIS large and handsome volume of 753 pages 
is a collection of physical constants com- 
piled under the auspices of the French Physical 
Society by Profs. Abraham and Sacerdote, and 
printed in the excellent style with which one is 
familiar in the publications of Messrs. Gauthier- 
Villars. 
Following the custom of the more recent editions 
of Landolt and Bérnstein’s Tables and the new 
Annual International Tables of Constants, the 
work has been divided among a number of 
specialists, and each page bears the name of the 
individual responsible for it. 
The system adopted has particular advantage in 
a volume planned with the idea of giving in general 
only one value for each constant. Reference is 
usually given to the name of the authority cited and 
the year of publication, but the source of the 
particular information is not specified. A useful 
explanatory paragraph with formule generally 
precedes each table. 
A novelty is the introduction of a large number 
of curves: For example, the curves of the physical 
properties of gases given by Amagat impart at 
a glance an amount of information which would 
have required a table of many columns. Some 
very fine reproductions of spectra are given, in- 
cluding a large-scale reproduction of the iron 
spectrum, which should be extremely useful. 
An examination of the book and frequent refer- 
ence to it for constants required in actual work 
has revealed only few errors, and on the whole the 
work of the compilers appears to have been well 
done and the subject matter judiciously chosen. 
Among the more interesting novelties are the 
useful sections devoted to wireless telegraphy and 
to physical measuring instruments, and no one 
could have been found to write with more authority 
on alloys than M. Le Chatelier. 
Some eccentricities appear in the initial table 
on units; few physicists are familiar with such 
terms as “volume massique” and ‘‘masse volum- 
ique,” ‘“degré carré,” and “steradian.” 
In the table of the specific heat of water the 
results of nine different observers are given, in 
most cases to four decimal places. But the 
“valeurs combinées” are given to five places, 
although examination of the individual values 
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shows large discte Mapics ing thevthird decimal. 
It is much better to averkEin-a case of this kind 
a fallacious air of precision, and it would have 
been wiser to have followed the example of Com- 
mandant Defforges, the well-known authority on 
pendulum observations, who told an eminent phy- 
sicist with whom he was discussing his work :— 
“Fach year, as I know a little more of the diffi- 
culties, I suppress a decimal place in my results.” 
A good feature of the index of organic bodies 
is that in many cases the common name of a sub- 
stance is given as well as its other names, perhaps 
only adopted by the chemists during a period of 
some passing fashion. For example, benzophenone 
is to be found in the index, as well as its 
synonyms, diphenylmethanone, diphenylketone, 
and benzoylbenzene. On the other hand, formalde- 
hyde is not to be found, although four other names 
of this body appear in the index. 
It is, however, surprising to find repeated the 
old familiar error, the confusion of benzine and 
benzene, words which in no language mean the 
same thing, although in some their pronunciation 
is unfortunately identical. 
In some cases almost too much information is 
given. Thus, for example, the work of Tammann 
and his associates on the influence of pressure on 
the melting point of a large number of substances 
is quoted in detail, while practically nothing is to 
be found on the even more important effect of 
pressure on the boiling-point, excepting for a few 
For dp/dt for sulphur vapour is 
° per mm., now 
ie 
organic bodies. 
given Regnault’s old value, 0°82 
known to be considerably too low. 
Perusal of a work of this magnitude is sugges- 
tive in showing how great is our ignorance in 
many important branches of knowledge, where it 
might have been imagined much more precise and 
accurate data would have been to hand. A good 
example is the subject of thermal radiation, trans- 
parency, etc., where we still depend on Leslie, 
Rumford, Melloni, and other pioneer workers, 
who showed the way, where comparatively few 
have followed to repeat their work with modern 
appliances. J. A. HARKER. 

THE PRESERVATION OF WILD LIFE IN 
AMERICA. 
Wild Life Conservation in Theory and Practice. 
By Dr. W. T. Hornaday. Pp. vit+240. (New 
Haven: Yale University Press; London: Ox- 
ford University Press, 1914.) Price 6s. 6d. net. 
ORTH AMERICA, when first opened up by 
Europeans, possessed a big-game fauna 
which, although poor in species, in point of num- 
bers was equalled only by that of southern and 
M 
